Estimation of Arctic windspeeds and stresses with impacts on ocean–ice snow modeling

Climatologically averaged windspeed distributions, observed on ships and drift stations over the Arctic Ocean, are evaluated to form a basis for discussing different estimations of climatological mean reanalysis windspeeds and stresses. The various reanalysis speed and stress estimations show differences in magnitude as well as spatial pattern, where especially the NCEP-provided windstress seems overestimated. The discussion is supplemented by a sensitivity study, where various windstress estimations are applied to force a coupled ocean–ice snow model. Differences with respect to ice conditions, surface salinity, freshwater and heat contents, integrated over the top 1000 m, are evaluated. Over the range of windspeed and stress estimates, ice thickness varies by 1.5 m, differences in freshwater content are about 4 m in the Canada Basin and deviations in the vertically integrated heat content reach up to 2.8 GJ m−2 in the Eurasian and 1.0 GJ m−2 in the Canada Basin. It is shown that the difference in windstress magnitude takes over an important role. A reduction of the windstress magnitude by 25% leads to a decrease in ice thickness of almost 1.0 m in the Canada Basin and reduces Fram Strait ice export by about 450 km3 year−1. It also leads to a decrease of about 2 m in the vertically integrated freshwater content of the central Canada Basin and an increase of 0.4 GJ m−2 in the corresponding heat content.